1. Field of the Invention
The present invention relates to a process for improving the properties of thermoplastic hydrocarbon polymers, and more particularly, to a process for reducing the melt viscosity of high molecular weight hydrocarbon polymers while retaining luster in fibers produced from the polymers. 2. Description Of The Prior Art
Processes for improving the melt viscosities and other properties of high molecular weight hydrocarbon polymers by degradation have been developed and utilized heretofore. For example, U.S. Pat. No. 3,144,436 issued Aug. 11, 1964, describes a process for improving the processibility of high molecular weight stereoregular hydrocarbon polymers whereby the polymers are reacted with a free radical initiator. The reaction of a free radical initiator, such as a peroxidic compound, with a high molecular weight polymer brings about a controlled polymer chain scission whereby the polymer molecular weight and melt viscosity are reduced. Such a reaction can be conveniently carried out in a conventional screw-type extruder apparatus.
While the above-described process successfully improves the properties of high molecular weight hydrocarbon polymers such as high molecular weight stereoregular polypropylene, it has been found that when fibers are produced from the treated polymer, such as in a melt spinning method, the fibers lack luster. Thus, there is a need for an improved process for reducing the melt viscosity of high molecular weight hydrocarbon polymers which at the same time increases the luster of fibers produced from the polymers.